Visual field studies: The nature of the deficit in functional tunnel vision induced by hypnosis as well as waking instructions will be analyzed by a spatial forced choice technique. Developmental studies: Using a two alternative forced choice method, an attempt will be made to study the functional visual field developmentally. With the Lipsitt non-nutritive sucking method, shape and size constancy will be studied in 1-3 month infants. Accommodation: The feasibility of the amelioration of night as well as the other anomalous myopias based on a prescription derived from the intermediate dark focus of individual subjects will be studied. Adaptation of the laser optometer for the clinical environment will be investigated. The nature of the stimulus to accommodation and its relationship to the intermediate dark - focus, the interval of Sturm, and chromatic aberration will be studied. Stress: With the cooperation of the Human Performance Laboratory, the effect of cardiovascular stress on the functional visual field and the dark - focus of accommodation will be studied. Oculomotor adjustments: The relationship between accommodation and convergence under reduced conditions as well as their relative modifiability will be analyzed.